JPH0819797A - Dehydration of sludge - Google Patents

Abstract

PURPOSE:To perform the flocculating sedimentation treatment and sludge dehydration treatment of living waste water such as excretion or sewage or industrial waste water by using a high molecular flocculant dissolved by water containing a large amt. of an electrolyte. CONSTITUTION:A polyfunctional monomer is added to all of monomers within the range of 0.0005-0.003wt.% and the resulting monomer compsn. is polymerized to prepare a cationic vinyl polymer which is, in turn, dissolved by water containing 50ppm or more of an electrolyte to be used in the dehydration of sludge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of dissolving a polymer flocculant in water containing a large amount of electrolyte, and subjecting domestic wastewater such as human waste and sewage or industrial wastewater to coagulation sedimentation treatment and sludge dewatering treatment. Is.

[0002]

2. Description of the Related Art City water, industrial water, etc. are generally used for dissolving high molecular flocculants used for dehydration and coagulation precipitation of excess sludge produced from sewage, night soil and industrial wastewater.

However, in recent years, in regions or companies where there is a shortage of city water or industrial water, it is unavoidable to use seawater, groundwater containing seawater, or treated tertiary treated water.

[0004]

[Problems to be Solved by the Invention] When the polymer flocculant is dissolved in water containing a large amount of electrolyte such as seawater or groundwater containing seawater or treated water after treatment, sufficient performance is not exhibited. In many cases.

The present inventors have arrived at the present invention as a result of research aimed at solving these problems.

[0006]

According to the present invention, the polyfunctional monomer is contained in an amount of 0.0005 wt% to 0.0
A sludge dewatering method is characterized in that a cationic vinyl polymer added and polymerized in a range of 03 wt% is dissolved in water containing an electrolyte, and the dissolved water is added to dehydrate the sludge.

[0007]

[Function] When seawater containing an electrolyte or dehydrated water is used as the water for dissolving the polymer flocculant, it is considered that the polymer causes the formation of yarn.

[0008] However, in the case of a polymerized product obtained by adding a polyfunctional monomer, even if it is dissolved in dissolved water containing an electrolyte, the formation of yarn bran is suppressed to some extent, and even if it is added to sludge, coagulation sedimentation or dehydration treatment is possible. It is supposed to become.

The present invention will be described in detail below.

As the cationic vinyl polymer used in the present invention, one or two nonionic vinyl monomers are used.
Copolymers obtained by polymerizing one or more and one or more cationic vinyl monomers with one or more polyfunctional monomers, and a cationic vinyl monomer 1.
There are copolymers obtained by polymerizing one or more polyfunctional monomers by adding one or more polyfunctional monomers.

Furthermore, by adding one or more non-ionic monomers to one or more polyfunctional monomers to form a copolymer obtained by polymerization, and then modifying the functional groups. A method of finally using a cationic polymer may be used.

For example, a method may be used in which methylenebisacrylamide is added in advance to polymerize acrylamide to form polyacrylamide, which is then converted into a cationic polymer by a Mannich reaction, a Hoffmann decomposition reaction and the like.

The vinyl monomer used in the present invention is (a) nonionic, (b) cationic and water-soluble.

The specific examples are as follows. (A) Nonionic vinyl monomer (meth) acrylamide, vinyl methyl ether, vinyl ethyl ether, etc.

(B) Cationic vinyl monomer The following (1-A), (2-A), (3-A), (4
-A) selected from the group.

(1-A) Quaternary nitrogen-containing (meth) acrylate [(meth) acrylate refers to acrylate or methacrylate. The same applies below. ]

(I) (meth) acryloyloxyalkyltrialkylammonium salt such as 2- (meth) acryloyloxyethyltrimethylammonium chloride,
2- (meth) acryloyloxyethyltrimethylammonium methosulfate, 2- (meth) acryloyloxyethyltriethylammonium ethosulfate, 3
-(Meth) acryloyloxypropyldimethylethylammonium methosulfate and the like.

(Ii) (meth) acryloyloxyhydroxyalkyltrialkylammonium salt such as 3-
Methacryloyloxy-2-hydroxypropyltrimethylammonium chloride, 3-methacryloyloxy-2
-Hydroxypropylmethyldiethylammonium chloride, 3-methacryloyloxy-2-hydroxypropyltrimethylammonium methosulfate and the like.

(2-A) Salt of tertiary nitrogen-containing (meth) acrylate and acid

(I) Dialkylaminoalkyl (meth)
Acrylate salts such as 2-dimethylaminoethyl (meth) acrylate sulfate and 2-diethylaminoethyl (meth) acrylate hydrochloride.

(Ii) Dialkylaminohydroxyalkyl (meth) acrylate salts such as 3-dimethylamino-2-hydroxypropyl (meth) acrylate hydrochloride, 3-diethylamino-2-hydroxypropyl (meth) acrylate sulfate and the like.

(3-A) Quaternary nitrogen-containing (meth) acrylamide

(I) (Meth) acrylamidoalkyltrialkylammonium salt such as 3-acrylamidopropyltrimethylammonium chloride, 2- (meth) acryloylaminoethyltrimethylammonium methosulfate.

(Ii) (meth) acrylamidohydroxyalkyltrialkylammonium salt eg 3-
(Meth) acryloylamino-2-hydroxypropyltrimethylammonium chloride, 3- (meth) acryloylaminoethyltrimethylammonium methosulfate and the like.

(4-A) Salt of tertiary nitrogen-containing (meth) acrylamide with acid

(I) Dialkylaminoalkyl (meth)
Acrylamide salts such as 2-dimethylaminoethyl (meth) acrylamide hydrochloride and 2-diethylaminopropyl (meth) acrylamide sulfate.

(Ii) Dialkylaminohydroxyalkyl (meth) acrylamide salts such as 3-dimethylamino-2-hydroxypropyl (meth) acrylamide acetate, 3-diethylamino-2-hydroxypropyl (meth) acrylamide sulfate and the like.

As the polyfunctional monomer, N,
Divinyl compounds such as N'-methylenebisacrylamide, N, N'-methylenebismethacryamide, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, divinylbenzene, vinyl methylol compounds such as methylol methacrylamide , Vinyl aldehyde compounds such as acrolein, and vinyl compounds such as methyl acrylamide glycolate methyl ether.

The polyfunctional monomer of the polymer used in the present invention is 0.000 based on the total amount of the water-soluble vinyl monomer.
It is a mixture of 5 to 0.003 wt% and copolymerization.

If the amount of the polyfunctional monomer is less than 0.0005 wt%, only the effect equivalent to that of the commonly used polymer flocculant can be obtained, and if it exceeds 0.003 wt%, the amount added to sludge becomes too large. The effect cannot be recognized within a realistic range of addition amount.

The cationic degree of the cationic vinyl polymer used in the present invention (cationic polymer flocculant physical property display method and analysis method-3, Polymer Coagulant Industry Association) is 1 meq.
/ G or more, preferably 1.5 meq / g or more is particularly effective.

The electrolyte contained in the dissolved water is mainly an alkali metal or alkaline earth metal salt, for example, potassium chloride, sodium chloride, calcium chloride, magnesium chloride, ammonium chloride, potassium sulfate, sodium sulfate, calcium sulfate, Examples thereof include ammonium sulfate, sodium nitrate, potassium nitrate and the like.

One or two or more of these electrolytes may be contained in the dissolved water.

The effect is remarkably exhibited especially when the concentration of the electrolyte in the dissolved water is 50 ppm or more.

The polymer used in the present invention can be copolymerized by a commonly used known polymerization method.

Particularly preferred is a method of copolymerizing the water-soluble vinyl monomer and a small amount of a polyfunctional monomer in a hydrophobic surfactant and an organic solvent. If necessary, a chain transfer agent, a chelating agent, etc. can be used.

Further, the polyfunctional monomer may be added before, during, or after the polymerization.

For example, an aqueous solution containing a water-soluble vinyl monomer and a polyfunctional monomer and an organic dispersion medium containing a hydrophobic surfactant having an HLB of 3 to 6 are mixed and emulsified, and then a radical polymerization catalyst is present. There is a method of producing a water-in-oil type cationic polymer emulsion by polymerizing at a temperature of 30 to 80 ° C. (Japanese Patent Application No. 61-236250).

To this water-in-oil emulsion, a hydrophilic surfactant is added and mixed with water, and the emulsion is converted into an oil-in-water emulsion for use.

The method for obtaining the cationic polymer of the present invention is as follows:
A method in which a cationic polymer is finally obtained by modifying the functional group may be used. For example, a method in which acrylamide is preliminarily polymerized to form polyacrylamide, which is then converted into a cationic polymer by a Mannich reaction, a Hoffmann decomposition reaction, or the like is included.

The polymer used in the present invention may be in the form of powder or liquid such as emulsion and suspension, but emulsion having good water dispersibility is preferable.

When such a polymer is dissolved in dissolved water containing an electrolyte of 50 ppm or more, added to various sludges and waste water, and mixed with stirring, flocs are formed. Add polymer to sludge,
The method of stirring and mixing is not limited because it varies depending on the condition of the sludge to be treated, but for example, a solution obtained by dissolving the polymer of the present invention in an amount of 0.2 wt% with respect to the evaporation residue of sludge (by the sewer test method) is used. 0.1wt% polymer active ingredient
% Or more and 5 wt% or less, preferably about 2 to 0.3 wt% is added, and rapid stirring is performed for a short time to form flocs, which are then dehydrated.

Hereinafter, the present invention will be described more specifically with reference to examples.

[0044]

Examples and Comparative Examples 300.0 g of dimethylaminoacrylate methyl chloride quaternary compound (DMAEA), 100.0 g of acrylamide, and 0 g of methylenebisacrylamide (MBA) (Sample A, 0 wt).
%), 0.004 g (Sample B, 0.001 w
t%), 0.01 g (Sample C, 0.0025)
wt%), 0.02 g (Sample D, 0.005
wt%) was dissolved in 307 g of distilled water to prepare an HLB solution.
15.4 g of 4.2 nonionic surfactant was poured into 204.7 g of paraffin oil and emulsified with a homogenizer.

This was degassed with nitrogen gas, and a water-soluble azo catalyst was added to polymerize it.

These polymers were dissolved in water containing seawater (electrolyte concentration: 625 ppm), and surplus sludge (TS (evaporation residue) 2.00 of activated sludge collected from a sewage treatment plant was dissolved.
%, SS (suspended substance) 1.84%) and stirred with a CST mixer at 1000 rpm for 30 seconds, and then visually compared to determine the floc size standard chart, then poured on a screen of 60 mesh and the amount of drained water after 10 seconds is measured. did.

Further, the sludge remaining on the screen was dehydrated with a centrifuge tube type centrifugal separator at 2000 rpm for 5 minutes to measure the water content. Table 1 shows these results and the results when dissolved in distilled water.

From Table 1, according to the method of the present invention, sludge can be efficiently dehydrated.

The above polymer was dissolved in the tertiary treated water of a food factory (electrolyte concentration: 152 ppm), and surplus sludge (TS 1.36%, SS 1.14) of activated sludge collected from the factory.
%) And stirred with a CST mixer at 1000 rpm for 30 seconds, and then visually compared to determine the floc size standard chart. Then, the mixture was poured onto a 60 mesh screen and the amount of drainage after 10 seconds was measured.

Further, the sludge remaining on the screen was dehydrated with a centrifuge tube type centrifugal separator at 2000 rpm for 5 minutes to measure the water content. Table 2 shows these results and the results when dissolved in distilled water.

From Table 2, according to the method of the present invention, sludge can be efficiently dehydrated.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

According to the present invention, sludge can be efficiently dehydrated by dissolving the polymer coagulant in water containing a large amount of electrolyte and adding it to the sludge.

Continued Front Page (72) Inventor Masuzou Machida 1190 Kasama-cho, Sakae-ku, Yokohama Mitsui Scitech Co., Ltd. Ofuna Technical Research Institute

Claims (1)

[Claims] 1. A cationic vinyl polymer produced by adding a polyfunctional monomer in an amount of 0.0005 wt% to 0.003 wt% with respect to the total amount of the monomers, and adding 50
A sludge dewatering method, characterized in that the sludge is dehydrated by dissolving with water containing at least ppm.